1. Field of the Invention
This invention relates to endoscopes, and more particularly to an endoscope wherein a solid state imaging device is provided at the forward end of an insertion portion and an object of interest is displayed for observation on a television screen or the like in response to a video signal obtained from the solid state imaging device.
2. Description of the Prior Art
Many conventional endoscopes have been constructed such that an objective lens and an eyepiece lens are disposed at opposite end portions of an image transmission optical fiber bundle, an image of an object of interest is focused at an end face of the optical fiber bundle through the objective lens, and the image which is transmitted through the optical fibers and appearing at the opposite end face is observed through the eyepiece lens. More specifically, as shown in FIG. 1, the conventional endoscope comprises a main body 10 of the control section, a flexible insertion section 12 connected to main body 10 of the control section, for insertion into a very deep portion of a living body or the like, and a cable 16 for connecting a control unit 14 incorporating various control mechanisms including a light source necessary for the endoscope to the main body 10 of the control section.
In fiberoptic endoscopes of this type, i.e., having an image transmission optical fiber bundle for transmitting an optical image of an object, which is observed through an eyepiece lens, the control section main body 10 comprises a grip section which can be necessarily grasped by one hand of an operator and an eyepiece section 17 disposed upwardly of this grip section and on the uppermost end of the control section 10. More specifically, as shown in FIG. 2, a grip section 10A connected to the rear end of an insertion section 12 is formed at the lower end portion of the main body 10 of control section, and further, an eyepiece section 17 including an eyepiece lens is provided on the top portion of the main body 10 of control section. Provided on the front face of the main body 10 of the control section are a first control button 18 for air and water supply and a second control button 20 for suction. With the above-described arrangement, in the control section of the endoscope, as shown in FIG. 2, the operator grasps the grip section 10A of the main body 10 of control section with a middle finger 22A, a third finger 22B and a little finger 22C of his left hand and operates the first or second control button 18 or 20 with an index finger 22D, while looking into the eyepiece section 17.
However, when using the conventional endoscope shown in FIGS. 1 and 2, to look into the eyepiece section 17, the operator is required to bring the main body 10 of control section close to his face by raising his arm, otherwise to bring his head close to the eyepiece section 17 by bending his body forward. Therefore, the operator will be obliged to assume an unnatural posture, undesirably resulting in that his arm, waist and the like become numb after a long periods of observation.
The cable 16 connecting the main body 10 of the control section to a control unit 14 is connected to an upper rear end portion of the main body 10 of the control section through a bendingly fastened portion 24. Because of this, a space necessarily must be provided between the main body 10 of control section and the front of the body of the operator, and, when the main body 10 of control section is rotated to apply a twist or the like to the insertion section 16, the arm of the operator and the main body 10 of control section may be twined around with the cable 16, thus interfering with operation.
Recently, on the other hand, there has been proposed an endoscope of the type, wherein a solid state imaging device such as a charge coupled device (CCD) or a metal oxide silicon (MOS) image sensor is provided at the forward end of the insertion section of the endoscope, and a video signal of the object of interest obtained from this solid state imaging device is displayed on a screen of a monitor television or the like, so that the object can be observed. Such devices eliminate the need for an eyepiece section 17 and reduce fatigue during operation for extended periods and result in easy handling. Furthermore, there is no need for the operator to look into the eyepiece section 17, thus enabling increased freedom of operator movement. Therefore, it is desirable to adopt a positional arrangement for connecting cable 16 and control section 10 to the control unit 14 which minimizes interference during use.